Zika Virus Spreads to U.S.
It is virtually impossible to watch a newscast and not hear mention of the Zika virus. The latest revelation is of an individual in Dallas being infected via sexual transmission. In this instance, a person traveled to an area where Zika was present and transmitted the virus to a partner (who had not been outside the greater Dallas area) upon returning to Dallas and having intimate relations. Both partners developed symptoms and subsequently tested positive for Zika.
So what does this mean?
The emergence of a novel disease – a new strain or one not previously seen in a location – often brings uncertainty. Zika was first identified in 1947 by scientists in Uganda researching Yellow Fever. The first human case was identified in Nigeria in 1954. For the next half-century, few confirmed cases of Zika virus infection were observed in Africa and Southeast Asia, possibly because incidents were rare, due to limited public health infrastructure, or because the symptoms are relatively minor and therefore not likely to be reported. In 2007, major epidemics began on Yap Island and have spread across French Polynesia and to other Pacific Islands as far as Easter Island. In 2014, the virus appeared in Brazil, possibly carried by travel-related to the FIFA World Cup played that year. The Aedes aegypt and Aedes albopictus mosquitoes that carry Zika (and other Flaviviridae viruses such as dengue, yellow fever, West Nile and Japanese encephalitis) thrive in Brazil’s hot and wet climate. The disease has since spread across Central and South America and, now, to North American as well.
As with any emerging disease, the precise methods of spread are not well understood. Recall that until significant global attention was paid and survivors were identified, science was unaware that the Ebola virus persists in the conjunctiva (surrounding the eyes) and in semen. Also consider that a year ago, experiencing fever, rash, joint pain and red eyes would not have prompted a test for Zika, a then relatively unknown virus. As more information is discovered, better understanding of this disease will emerge.
The primary danger of Zika appears to be to unborn children, who develop microcephaly. There are also reported cases in Brazil of Guillain-Barré Syndrome, an inflammatory disorder of the peripheral nerves outside the brain and spinal cord that can result in paralysis. There is no vaccine or prophylactic medication available to prevent Zika virus infection.
Pregnant women, those who may become pregnant and their sexual partners should limit or avoid travel to the most severely impacted regions as reported by the CDC. When traveling to such a region, take precaution to prevent infection: wear long-sleeved shirts and long pants, use U.S. Environmental Protection Agency (EPA)–registered insect repellents, use permethrin-treated clothing and gear and stay and sleep in screened-in or air-conditioned rooms. The CDC also recommends the use of condoms to reduce the chance of sexual transmission of the virus.
It is important to note that mosquitoes that spread Zika virus bite both indoors and outdoors, mostly during the daytime; different from what we expect in the U.S. where mosquitoes come out mostly at dawn and dusk. These mosquitoes, A. aegypt and A. albopictus, can be found from West Texas eastward, across the Midwest and ranging as far north as Connecticut. They are particularly viable in regions with hot, wet climates and standing water.
Like West Nile before it, Zika is here to stay. Until a vaccine or treatment can be developed, the best protection is awareness.